JPS60212684A - Screw rotor - Google Patents

Abstract

PURPOSE:To facilitate manufacturing work of a rotor and improve its sealing and lubricating performance so as to improve efficiency of a compressor, by using the screw rotor, having an improved novel tooth curve, for the screw compressor. CONSTITUTION:A compressor comprises female and male rotors which rotate while meshing with each other around parallel two axes. During rotation of, for instance, the male rotor, a circular arc of radius R4, having the center O4 on a radial line extended at an angle thetar5 with a straight line connecting rotary centers of each rotor, detaches said center O4 from the connection line. And the male rotor forms its curved part between points C1 and D1 by a circular arc of radius R5 around the rotary center of the male rotor, curved part between points D1 and E1 by an envelope by a circular arc D2-E2 and a curved part between points E1 and F1 by an envelope by a circular arc F2-G2 both being a part of the tooth groove of the female rotor. Then the rotor provides in a tooth profile of the female rotor an addendum Af while in a tooth profile of the male rotor an addendum Dm corresponding to the addendum Af.

Description

Detailed Description of the Invention Technical Field The present invention relates to a pair of screws used in a screw machine that transfers a compressible fluid while compressing or expanding it.
Regarding the rotor, in particular its tooth profile.

PRIOR ART A screw rotor with an asymmetric tooth profile, which is generally used in compressors for compressible fluids, has a male rotor with the main part of the tooth profile outside the pitch circle of the rotor, and a male rotor with the main part of the tooth profile outside the pitch circle of the rotor. Usually consists of a combination with a female rotor inside.

A male rotor with several teeth is meshed with a female rotor with a slightly larger number of teeth, and the tip diameter of the male rotor and the pitch diameter of the female rotor are approximately equal to each other. are set to be equal.

A pair of screw rotors of this type are two cylindrical spaces whose axes are parallel to each other and whose diameter is equal to the outer diameter of each rotor, and the distance between their axes is less than the sum of their mutual radii. It is rotatably housed in a short casing having a space whose axial length is the same as the axial length of the rotor, and both open ends of the casing are closed with end plates.
A screw compressor or an expander is constructed by providing a fluid suction port and a fluid discharge port 1, respectively [see Figures 3(a) and 3(11j)].

When the above device is used as a compressor, the female rotor is rotated counterclockwise and the male rotor is rotated clockwise as shown in the figure.In this case, regarding the tooth profile curve of the female rotor, , in the curve forming the tooth groove,
The curve on the front side in the rotational direction is called the forward tooth profile, and the curve on the rear side in the rotational direction is called the follower tooth profile. Similarly, the curve on the front side in the rotational direction is called the forward tooth profile and the curve on the rear side in the rotational direction for the curve forming the tooth profile of the male rotor. The side curve will be referred to as the following side tooth profile.

When the device is used as an expander, the names of the respective curves are reversed; however, in the description in the drawings of Specification 9 of the present invention, the names related to the tooth profile curves will be explained in accordance with the above definitions in all cases.

Figures 1(a) and 1(b) show each tooth profile curve seen when the rotor is cut by a plane perpendicular to the rotational axis of the screw rotor, that is, the screw profile at the longitudinal axis end face of each rotor. This shows the meshing state of the rotor tooth profiles. Figure 1(a) shows the state of engagement of the tooth profiles of the two rotors immediately after the female rotor tooth profile following side tooth tip curve and the male rotor tooth profile following side tooth tip curve begin to contact. This shows the phase of the tooth profile, and then the male rotor rotates about 20 degrees until the phase shown in Figure 1 (b), that is, the highest part of the tooth profile curve of the male rotor and the deepest part of the south groove of the female rotor are opposite to each other. It rotates through a state of

The above-mentioned tooth profile curve is a tooth profile that has been practiced by the applicant of the present invention (see Japanese Utility Model Publication No. 54-25552), and its characteristics are as follows.

That is, in the figure, 1 is a male rotor, S is a female rotor that meshes with the male rotor 1, and these rotors 1. Su is
By rotating in the direction of the arrow within a casing (not shown) around the rotation center (pitch circle center) 3.4, each of them functions as a fluid compressor. 15
and 16 are the pitch circles of the male rotor 1 and the female rotor, respectively, and the straight line connecting the rotation centers 3 and 4 is the contact point 17. of the pitch circles 15 and 16. That is, it passes through pitch point 17.

Referring to FIG. 1(b), for convenience of explanation (1) female rotor tooth profile (a) forward curve; on straight lines 3 and 4, from point 12 at the deepest part of the tooth profile center of the female rotor to the tip 1 of the tooth profile A circular arc 11 facing in the ° direction and having a radius r with the pitch point 17 as the center
12 and the outer portions 11 to 10 of the same circular arc, passing through the rotation center 4 of the female rotor and having the radius t4.
The curve between 12 and 13 at the bottom of the female rotor groove is a circular arc centered on the rotation center 4 of the female rotor and has a radius r, and the outer diameter of the tip circle The range between 10 and 14 is made to match the pitch circle 16 of the female port.

(17) Follow-up side curve: 13~ on the follow-up side of the female rotor groove
Let the curve 14 be an epitocolloid curve created at point 8 on the tooth profile of the male rotor.

It is formed by smoothly connecting closed curves to -.

(2) Male 1-rotor tooth profile (a) Advance side curve; From the center apex 7 of the male rotor tooth profile,
The curve leading to the point 6 toward the tooth base is centered at the contact point (pitch point) 17 of the pitch circles 15 and 16 of both the female and male rotors, and the radius r3 is smaller than the radius r4 by the amount of gap required for rotation. Let it be a circular arc having a radius of , and let the period from point 6 to tooth root 5 be an envelope formed by a straight line between tooth tips 10 and 11 of the female rotor.

(ol Following side curve; point 7 on the following side of male rotor tooth profile
8 is an arc whose center is the rotation center (pitch circle center) 3 of the male rotor and radius r1, and the curve from point 8 to dedendum point 9 is the opposite tip of the tooth of the female rotor. Point 1
4, and by making the diameter between 9 and 5 of the bottom of the tooth groove coincide with the pitch circle 15 of the male rotor, point 8 can be set to the ridge line -L along the ridge.
The contact line of both the female and male rotors reaches the compression chamber closing side junction of the cylinder housing the two motors. Also, connect the points 8 to the rotation centers 3 and 4 of each motor. 3. The conventional tooth profile of the 1st (b) kokutate, which is formed far away from the straight line (X:M!+), is defined as described below, so (a) the r-hole between the working spaces is 3, (b) lNb) In the figure shown, the male 1r-Yuyama-shaped point 8
In addition, the space 18 created at the tooth-shaped contact area between the low-pressure side end plate and the male and female routers is formed far away from the X-axis. Since the ratio of this is smaller than that of the tooth profile used by other companies, which will be described later, there is less power loss due to the vacuum generation effect based on volumetric expansion.

While there are advantages, such as those mentioned in Section F, problems have also been pointed out. That is, ()9 The space volume is small (the stroke volume is small).

2) Because the groove bottom of the female rotor tooth profile is uneven, the sealing performance cannot be said to be good, and it is difficult to measure the dimensions during processing. Furthermore, the cutter profile is uneven and complicated, resulting in poor processing efficiency.

(e) Since the follow-up side curve of the tooth profile is created as a point, the sealing point is likely to wear out, making it difficult to maintain the sealing effect.

(f) The pressure angle of the tooth profile near the pitch circle is almost zero, making it difficult to machine with high precision and the life of the machining tool is short. Particularly when bobbing the screw rotor, the life of the hobbing tool is shortened.

Note that the contact surface 18' of both tooth profiles shown in FIG. 1(a) in the initial meshing phase is approximately 20 m
Since the space 18 expands in the phase shown in FIG. It is preferable that the volume of is not large. The characteristic tooth profile described above has a smaller rate of volumetric expansion than those described below.

For example, one of the conventional tooth profiles used by other companies, Tokuko Sho 56-1
The tooth profile of the rotor used in the screw rotor machine described in Publication No. 7559 is as shown in Figure 2, and in the figure, the configurations with the same symbols as in Figure 1 are the same as those in Figure 1. Since there is, I will omit the explanation. Note that the meshing phase of the tooth profile in FIG. 2 corresponds to that shown in FIG. 1fb). In the same figure, (1) Female rotor tooth profile (A) forward curve, 28-29; circular arc with radius r'1 centered at point 36 on straight line 17-29, 29-30; centered at pitch point 17; An arc of radius r'2.

(B) Follow-up side curve, 30-31; Epitocolloid curve by point 23 on male rotor tooth profile, 31-32; Part of straight line passing through r11 rotation center 4 of female rotor, 32-33; Centered on pitch circle 16 33 to 34; an arc centered on the rotation center 4;

34-35; Arc having its center on the pitch circle 16.

(2) Male rotor tooth profile (a) Advance side curve, 21-22; Female rotor tooth profile (circular arc with radius r'1 centered on point 36 on straight line 17-29)
envelope, 22-23; arc of radius r'2 centered on pitch point 17;

(B) Follow-up side curve, 23-24; Ebitrochoid curve by point 31 on female rotor tooth profile, 24-25; Straight line 31
Generated curves by ~32; 25-26; arc having its center on the pitch circle 15; 26-27; a circular arc having its center on the rotation center 3; 27-21; a circular arc having its center on the pitch circle 15.

However, the volume of the illustrated vacuum space 18 is
(b) It is much larger than the tooth profile shown.

Purpose Therefore, the present invention is based on the first method conventionally used by the applicant.
Without losing the above-mentioned advantages of the illustrated tooth profile, or with the least possible reduction of the above-mentioned advantages based on the technique of the present invention, it is possible to overcome the problems cited, namely, by increasing the stroke volume and sealing point. By changing the shape of the tool, we prevent wear by +1 to prevent a decrease in efficiency during the period of use, and by increasing the pressure angle, we aim to improve the machining accuracy of the tooth profile and tool life. The purpose is to provide a new chevron that can facilitate this. Note that other objects and effects will be made clear in the detailed description of the present invention described below.

Structure The tooth profile of the present invention will be explained below based on one embodiment not shown in the accompanying drawings.

FIG. 3 shows a compressible fluid compressor constructed by incorporating the screw rotor of the present invention, and FIG. 3(a) shows the following:
The side sectional view along the A-A line in the same (I)) figure.

FIG. 3(b) is a cross-sectional view taken along line BB shown in FIG. 3(a). In the figure, reference numeral 1 denotes a male rotor, which is rotatably driven by a rotating shaft 40 connected to a prime mover (not shown), and cooperates with a support shaft 41 extending symmetrically to the shaft 40 with respect to the rotor 1. , rotor 1 is rotatably supported by support portions 44 and 45 of end plates 42 and 43, respectively. The rotor 1 is a female rotor that meshes with the male rotor 1, and the rotor is also rotatably supported by end plates 42 and 43 by rotating shafts extending from each end surface thereof. 46 is
- a casing surrounding the outer periphery of a pair of intermeshed rotors 1 and 2, each of which is provided at its longitudinal end face with a low-pressure side end plate 42 having a fluid inlet 47 and a high-pressure side with a discharge port 48; An operating space 49 is formed and divided by the rotor teeth, the groove surface, the inner wall of the casing, and the inner walls of both end plates. The working space 49 includes a low pressure passage 50 and a high pressure passage 5 for the working fluid in the casing.
1, and has a suction port 47 and a discharge port 48, which communicate with each other. The cross section of the casing 46 has two cylindrical spaces arranged in parallel, and the distance between their center axes is smaller than the sum of the radii of each cylindrical space. Therefore, both cylindrical spaces have parts that overlap with each other, and the inner walls of the rain space intersect. A ridge line 52 appears at the location where the

In the female rotor 2, each spiral groove in the -thread is the rotation axis (longitudinal).
The grooves are mostly located inside the pitch circle of the rotor 2, and the height of the teeth separating the grooves is equal to the pitch. The groove protrudes slightly from the circumference, and the groove is formed by a concave curve within the recess.

The male rotor 1 is usually equipped with four helical teeth, and each drawing rack is along the rotation axis (longitudinal) direction, and has approximately 30 teeth around the rotation axis.
A torsion of 0" is given. The tooth height of the drawing rack extends partly inside the pitch circumference of the rotor, and most of it is located outside the pitch circle, and extends to the southeast adjacent to the drawing rack. A groove into which the teeth of the female rotor 2 fit is provided between them, and the cross section of the tooth profile consists of a curved line convex to the outside.The working space 49 is divided into a V-shape, and the low pressure side is After the communication between the suction port 47 of the end plate 42 and the working space is closed, the divided working space moves as the meshing line of the teeth of both rotors moves (relatively as the rotors rotate). The volume of the space is reduced compared to that at the deadline,
During this time, the fluid is adiabatically compressed and becomes high pressure and high temperature, and eventually the working space becomes a discharge port 48 formed in the high pressure side end plate 43.
When it communicates with the high pressure chamber 511111, it is discharged.

During this period, the rotor teeth, the engagement between the groove surfaces, the lubrication and airtightness of the sliding surfaces between the casing inner wall and the rotor end surface and the end plate inner surface (sealing action), and the compressible fluid In order to cool the rise in temperature due to adiabatic compression, cooled lubricating oil is injected into the working space through the nozzle 53.

The screw rotor of the present invention relates to a tooth profile of a rotor used in the above-mentioned compressor for compressible fluid.

Figures 4 (a), (1)), and (C) show the tooth profile curves seen in the cuts when the screw rotor of the present invention is cut along planes perpendicular to the respective rotational axes. is a male rotor, and 3 is its center of rotation, that is, the center of a pitch circle 15 of the male rotor tooth profile.The male rotor 1 meshes with the female rotor 2 and rotates around the center of rotation 3 in the direction of the arrow. Z is the female rotor, 4 is its rotation center, that is, also the center of the pitch circle 16 of the female rotor tooth profile;
The lotus meshes with the male rotor 1 and rotates around the center of rotation 4.
Rotate in the direction of the arrow until it becomes stiff. 17 is the pitch point, points 3, 17 and 4 are on a straight line, and the pitch circle 15,
16 is circumscribed at pit point 17. In addition, 18 is a vacuum space (vacuum creation space) created between tooth profiles. The meshing state of the illustrated tooth profiles is such that the phase shown in FIG. 4(b) shows that the male rotor 1 rotates about 10 degrees and the tooth profiles of both rotors first come into contact 18.
Fig. 4(c) shows a phase in which the male rotor has rotated approximately 20 degrees and both tooth expansion curves are most deeply engaged, as shown below. The description of the chevron curve will be based on FIG. 4(c).

Referring to FIG. 4(c), the tooth profile curves in the figure are each regulated by the following conditions. Note that Af is addendum, Dm is dedendum, and point A on the tooth profile curve.

is also a point on the pitch circle 16.

(+1 Female rotor tooth profile (a) Follow-up side curve; from the tooth tip to the tooth bottom side, fa)
IT, -A2; Male 'I - Point A on the evening tooth curve.

Created by, it touches A, -B at point A2.

(bl A, -B, ; An arc of radius R7 that is on a straight line that touches the pitch circle 16 at point A and has a center 07 outside the concave shape of the tooth space.

(c) B2-C2: Envelope curve formed by arcs B, -C, which are part of the male rotor tooth profile curve.

(b) Advance side curve; +d+ along the tooth bottom to the tooth tip side
D2-B2; Center 0. on the straight line 3-4 and outside the pitch circle 16. A circular arc with radius R1. Curve E at point E2
, -F,.

(e) B2-F; straight line 0. - A circular arc with radius R2 having center 02 on the opposite side from Ol on the extension line of B2. However, it is convex towards the tooth groove side. At point F, curve F, -G
, is in contact with .

(r) F2 G2; Straight line 0. - F, arc of radius R8 with center O8 above and outside the concavity of the tooth space; At point G, it touches the outer diameter of the female rotor.

(gl Gt B2: Female rotor outer diameter (h) c'
The curves B2-C, , D, and -E may be smoothly connected by straight lines or curves CI, =DI, which are in contact with each other.

(2) Male rotor tooth profile (A) Follow-up side curve; along the tooth root to tooth tip side, (J)
H+ A+: Created by point H on the female rotor tooth profile, and touches the male rotor root circle at point H1.

+k) A, -B, ; Part of female rotor tooth profile, arc A
2-1'(). At point B1, the curve B1-C,
come into contact with

(Ql n, -c, ; θr at straight line 3-4 and point 3
A radius line extending from the center of rotation of the male rotor intersecting the angles of 5 and 5 is a short circular arc having a center 04 at R4. However, the angle θr6 is relatively large, between 4° and 8°, and as a result, the center 04 is located far away from the axis #3-4. It touches curve C, -D at point C1.

'rnr C, r), ; It is a circular arc with radius R1 centered at point 3, and touches curve r), -E, at point D1.

(b) Advance side curve; from the tooth tip to the tooth root side, in)
D, -E, ; Part of female rotor tooth profile curve, arc D2E
2 (approximately D'2-E may be used). It touches curve E, -F at point E1.

(0) EI Fl ; Part of female rotor tooth profile, arc E
2-Envelope by F2. At point F, the curve F, -G.

be in contact with

(p) Fl-ct; Part of female rotor tooth profile, arc F2-
Envelope by G2. Point G is in contact with the rotor root circle.

(Q)　G1-Hl　; Male rotor tooth bottom circle.

They are each formed by:

Effect The characteristics of the tooth profile curve of the screw rotor of the present invention are as follows. 5, the angle θ1 formed by the tangent at point C0 and the perpendicular line υ to the straight line 3-4 is equal to the angle θ1 when the center 04 is placed on a radial line extending from the pitch point 17. ′
1, and the following side tooth profile curve of the male rotor is far away from the straight line 3-4 connecting the rotation centers of both rotors,
It approaches the tooth profile curve on the female rotor follow-up side, and the 9th and 18th can be made smaller.

(2) By varying the angle θys to a relatively large value,
Circular arc B1-C located on one radius line sandwiching angle θr6
1 center 0. Since it is set far away from the straight line 3-4, the space 18 can be made even smaller.

As described above, as shown in FIGS. 4(b) and 4(c), since the volumetric expansion coefficient of the space 18 is small, unnecessary power loss due to vacuum creation is small.

(3) Let the song @Rt-C1 be the envelope of arcs n and -c1,
Curve, -F, 1 to arc horse -E, song IIIel -
Fl is the arc E, -F, the curve F B -G @ is the arc F @ -G @, the curve A, -111 is the arc A, -1
Since the envelopes of 1 and 1 are used, the tooth profile slide 1111
Since the surfaces are in surface contact, the abrasion resistance of the area is improved.

(4) Referring to Fig. 6, since the toothed sliding surface makes surface contact as shown in , when lubricating oil E is supplied, the lubrication and sealing effect of the surface can be improved due to the wedge effect. can.

As described above, the wear resistance and sealing effect can be improved, and a decrease in efficiency can be prevented during long-term use of the screw rotor.

(5) Referring to Fig. 7, the curve A2-B2 is an arc having the center 07 outside the concave shape of the tooth space of the female rotor, so when the curve B2-C2 is extended to the outer diameter or Compared to the tooth profile in which the straight line connecting the center 4 and point B is extended to the outside diameter, the profile of the cutter that cuts the rotor tooth profile tends to have a wider hem, and the pressure angle can also be increased, so machining of the chevron shape is possible. Accuracy can be improved and tool life can be extended.

Furthermore, compared to the case where the curve B2-C2 is extended to the outer diameter, the space volume can be increased by the shaded area in FIG.

(6) Since the curve H2-A2 is created by point A on the tooth profile curve of the rotor, when the pressure angle θ2 at the tooth profile is extended from the curve A2-B2 to the outer diameter (up to H'2) can be made larger than that of θ'2, improving the machining accuracy of the tooth profile and extending the tool life.

Further, in FIG. 7, the space volume can be increased by a portion a indicated by diagonal lines.

(7) Referring to FIG. 8, since the curve D2-E2 is an arc having the center 01 outside the pitch circle 16 of the female rotor, the point D2 is at the same position and the center of the arc D2-E2 is the pitch circle. Compared to the case where the center 0□ is located on the outside of the pitch circle 16 (pitch point 11), the space volume can be increased by the shaded area in Fig. 8. .

Also, the pressure angle θ3 at point E2 is expressed by the arc r)2-B2
can be made larger than that θ'3 when the center is at the pitch point 17, so the pressure angle of the tooth profile curve forming B2-B2 can be made large.

(8) Referring to FIG. 9, draw the curve E, -F2 at its center 0. Center 02 on the opposite side
Therefore, the center 02 of the arc E2-F2 is on the same side O' as the center 08 of the arc D2-E2.
Compared to case 2, the space volume can be increased only in the shaded area in FIG.

Further, the pressure angle θ4 at point F on the tooth profile curve can be increased (/θ4>/θ−), and the pressure angle of the curve forming F2-F can be increased.

(9) Referring to Fig. 10, the curves F and -G are circular arcs with the center 08 outside the concave shape of the tooth space of the female rotor, so the circular arc E2-F2 is extended as it is to the outer diameter. Compared to the case, the space volume can be expanded by the shaded area in FIG.

Also, the pressure angle θ at point G2 on the tooth profile curve.

(/θ, 〉Zθ'5), F2-
The pressure angle of the curve 62 can be increased.

(10) By providing the addendum Af and the addendum Dm, the tooth profile space volume of the rotor can be increased, and the amount of air can be greatly increased.

As described above, the space volume can be increased as a whole to increase the amount of air, the pressure angle of the tooth profile curve can be increased, the machining accuracy of the tooth profile can be improved, and the life of -U l- can be extended3.゜(11) Conventionally, the seal point is a discontinuous point regardless of the location.
10th)) Mark in figure>4iB.

[See reference numeral 23 in Figure 2.] However, it was difficult to determine the exact position i1+11 using calipers, micrometers, butts, three-dimensional measurements, etc. because the tip of the filler f was spherical.

That is, with reference to Figure 111)j and Figure 1Nc1,
If there is a discontinuous point on the tooth profile curve, the exact position of the discontinuous point cannot be determined because the position of contact with the fissure f cannot be determined even when the same point is fixed. 1st
If 41: sea urchin curve fin, -c shown in Figure Na1 is made into a circular arc and a continuous curve, such a problem will not occur and the measurement will be easier. Therefore, it is easy to process an accurate chevron curve.

As described above, according to the chevron curve of the present invention, the gap between the pacuno and the created η is made large so that it does not become tr, and while retaining the advantages of the conventional tooth profile, the tooth profile of the sealing point is changed to a circular arc and a curved surface. The contact structure uses lubricating oil to create a wedge effect, effectively performing sealing and lubrication to reduce wear and prolong the sealing effect, thereby maintaining efficiency.
The space volume can be increased by providing m.

Moreover, since we were able to make the pressure angle in the vicinity of the pitch circle of the tooth profile relatively large, not only the machinability with the forming tool is good, but also the machining accuracy can be improved. Since it is not necessary to form corners, the tool can be easily formed and its service life can be extended.

This can extend the life of the hobbing tool and facilitate hobbing.

t ``Oh, addendum, even though the dedendum is provided, the blowhole is of a practically no problem as shown in Figure 4(a).

In summary, the present invention provides a screw rotor tooth profile that is excellent in workability, has a greatly increased capacity, is durable and efficient, and is useful in practice.

[Brief explanation of the drawing]

Figures 1, L and 2 are the chevron curves of conventionally used screw rotors; (a) From the one shown to the one shown in the figure, the meshing phase of the chevrons is different. Move to fh1 diagram. 3(at) and 3(1)1 are a full sectional view and a cross sectional view of a rotor machine using the screw/screw of the present invention, specifically an IE compressor, and FIG. The meshing position of the pair of rotor tooth profile curves is 1%tc, and the phase shown in Fig. 4(a) is sequentially shifted to the state shown in Fig. 4(c). Figs. 5 to 5 Figure 10 is an enlarged view of a part of the tooth profile to explain the characteristics of the chevron curve of the screw rotor of the present invention, and Figure 11 is an explanatory diagram of the method for measuring the tooth profile curve of the screw rotor of the present invention. Yes. 1......Male rotor 2
・・・・・・・・・・・・・・・・Female[! - rotors 3 and 4...rotor rotation centers 15 and 16...
Pitch circle 17・・・・・・・・・・・・・・・Pitch point 18
・・・・・・・・・・・・Vacuum creation space-27- Figure 3 (a) (b) 2- Figure 4 (a) (b) 1 15 Y 1 j /1' 4ノ■, Nini Mata Nicho Arrest 1□-1' 1 - ~type j -・7 ≧~ j / ・: I 'w / 1B" Figure 10 Figure 11 (a) (b) (C) Procedure Written amendment dated May 15, 1980 Kazuo Wakasugi, Commissioner of the Patent Office1, Indication of the case 1982 Patent Application No. 696992, Title of the invention Screw rotor 3, Relationship with the person making the amendment Patent application Person 4, Agent 107 Address: Calm Building 3, 8-4-7 Akasaka, Minato-ku, Tokyo
B6. Number of inventions increased by amendment None. 7. Amendments are made to the "Detailed Description of the Invention" column of the original specification of the application subject to the amendment and the attached drawings. Figure 4 (C) Procedural amendment April 4, 1985 Manabu Shiga, Commissioner of the Japan Patent Office1, Display of case 1982 Patent Application No. 696992, Title of invention Screw rotor 3, Person making the amendment Case Relationship with Patent Applicant Address: 113-14 Oatake Shinden, Bunsui-cho, Nishikanbara-gun, Niigata Prefecture, Attorney's Statement: 1. Name of the invention: Screw/rotor 2. Claims: (1) Parallel biaxial A screw rotor consisting of a female rotor and a male rotor that rotate while meshing with each other, each tooth profile of the female rotor has its main part formed within the pitch circle of the same rotor, and each tooth profile of the male rotor is In the type of rotor whose main portion is formed outside the pitch circle of the rotor, at least the tooth profile groove of the female rotor is formed in the addendum Af in each tooth profile curve formed in a plane orthogonal to the rotation axis of each rotor The curve TI connecting the point H on the tooth tip of the rotor and the point A2 on the pitch circle of the same rotor, =A,
Let be the generation curve by point A on the coater tooth profile,
Sequentially, point A between fi't and Bt. A circular arc with a radius R7 that is a straight line -12 that is in contact with the pitch circle and has a center O1 outside the tooth space. If the line between B and -C is part of the male rotor tooth profile, there is a straight line connecting the wrapping line and the rotation center of each rotor, with the center 0. A circular arc of radius R2 having a center 02 with Connecting curve H, -A, ←
-Special threat→feeding threat awn-Kiri is a generated curve by point H2 on the female rotor tooth groove, and sequentially +AllBl is a circular arc A2-B, which is a part of the female rotor tooth groove, Nyoru envelope, B
, -C, a circular arc A with a small radius R4 having a center 04 on a radial line extending at an angle or with a straight line connecting the rotation centers of each rotor at the rotation center of the male rotor, and connecting the center 04 with the above. An arc of radius R6 centered on the rotor's rotation center passing between C1 and D1, far away from the line, and
Between n and El, there is a circular arc that is a part of the female rotor tooth groove, -
The envelope by E2, El-F, is also connected by arc F2
This technical field relates to a pair of screw rotors, in particular, to a tooth profile curve formed by an envelope curve according to G2, and a female rotor tooth profile is provided with an addendum Af, and a male rotor tooth profile is provided with a dedendum Dm corresponding to the addendum Af. PRIOR ART A screw rotor with an asymmetric tooth profile, which is generally used in compressors for compressible fluids, has a male rotor with the main part of the tooth profile outside the pitch circle of the rotor, and a male rotor with the main part of the tooth profile outside the pitch circle of the rotor. Usually, a male rotor with a plurality of teeth is meshed with a female rotor with a slightly larger number of teeth than that of the male rotor, and the diameter of the tip of the male rotor is adjusted. and the center of the pitch circle of the female rotor are set to be approximately equal. A pair of screw rotors of this type are arranged in two cylindrical spaces whose axes are parallel to each other and whose diameter is equal to the outer diameter of each rotor, and where the distance between the axes is shorter than the sum of their mutual radii. In this way, a screw compressor or an expander is constructed by providing a fluid suction port and a fluid discharge port having a space whose axial length is the same as the axial length of the rotor. [See Figures 3(a) and 3(b)]. When the above device is used as a compressor, the female rotor will be rotated counterclockwise and the male rotor will be rotated in the "grand prize" direction as shown in the figure. For example, among the curves that form the tooth groove, the curve on the front side in the rotation direction is called the forward side tooth profile, and the curve on the rear side in the rotation direction is called the follower side tooth profile. Similarly, the curve forming the tooth profile of the male rotor is also called the forward side tooth profile. The curve on the front side will be referred to as the forward tooth profile, and the curve on the rear side in the rotational direction will be referred to as the follower tooth profile. When the device is used as an expander, the names of the respective curves are reversed, but in the description in the drawings of Specification 9 of the present invention, each tooth profile curve seen when referring to the tooth profile curve, that is, each rotor. This shows the meshing state of the tooth profile of the screw and rotor on the end surface of the longitudinal axis.
Figure 1(a) shows the phase of the tooth profiles of both rotors immediately after the female rotor tooth profile trailing side tooth tip curve and the male rotor tooth profile trailing side tooth tip curve begin to come into contact. rotates by about 20 degrees and rotates through the far phase shown in FIG. The above-mentioned tooth profile curve is a tooth profile that has been practiced by the applicant of the present invention (see Japanese Utility Model Publication No. 54-25552), and its characteristics are as follows. That is, in the figure, 1 is a male rotor, E is a female rotor that meshes with the male rotor 1, and these rotors 1. Eha,
By rotating the inside of the casing (not shown) in the direction of the arrow around the center of rotation (pitch circle center) 3.4, it functions as a fluid compressor. 1
5 and 16 are the contact points 17. of circles 15 and 16.
That is, it passes through pitch point 17. Referring to FIG. 1(b), for convenience of explanation (1) female rotor tooth profile (a) forward curve; on straight lines 3 and 4, from the deepest point 12 of the tooth profile center of the female rotor to the tip 10 of the tooth profile A circular arc 11 facing in the direction and having a radius r4 with the pitch point 17 as the center
12 and the outer portions 11 to 10 of the same arc, passing through the rotation center 4 of the female rotor and having the radius r4.
The curve between 12 and 13 at the bottom of the female rotor groove is formed by the straight lines 10 to 11 that are in contact with
It is a circular arc having radius r2 as the center, and the outer diameter of the tip circle between 10 and 14 is made to coincide with the pitch circle 16 of the female rotor. (b) Follow-up side curve: 13 to 1 on the follow-up side of the groove of the female rotor
4 is created by point 8 on the tooth profile of the male rotor!・Let it be a colloid curve. It is formed by smoothly connecting the above curves. (2) Male rotor tooth profile (a) Forward side curve: From the center m point 1 of the male rotor tooth profile,
The curve leading to the point 6 toward the tooth base is centered at the contact point (pitch point) 17 of the pitch circles 15 and 16 of both the female and male rotors, and the radius r3 is smaller than the radius r4 by the amount of gap required for rotation. Let the radius be a circular arc, and let the line from point 6 to tooth root 5 be an enclosing line formed by a straight line between tooth tips 10 and 11 of the female rotor. (o) Follow-up side curve; points 7 to 8 on the follow-up side of the male rotor tooth profile
The curve between is the center of rotation of the male rotor (pitch circle center)
3 as a center and radius r1 as a circular arc, and the curve from point 8 to root point 9 is the opposite point 1 of the tooth tip of the female rotor.
4, and by matching the diameter of the bottom of the tooth groove between 9 and 5 with the pitch circle 15 of the male rotor, point 8 is set as the female rotor on the ridge line along the thread. The contact line of both male rotors is determined so as to reach the intersection line of the compression chamber closing side of the cylinder that accommodates both rotors. Also, point 8 is connected to the straight line (X
formed far away from the axis). Since the conventional tooth profile shown in FIG. 1(b) is defined as described above, (a) blowholes between the working spaces can be made substantially zero. (b) 1st (b) As shown in the figure, point 8 of the male rotor tooth profile
By forming the space 18 far away from the X axis, the volume expansion rate of the space 18 created at the tooth-shaped contact area between the low-pressure side end plate and the male and female rotors as the rotor rotates will be as described below. Compared to tooth profiles used by other companies, there is less power loss due to vacuum generation action based on volumetric expansion. While there are advantages, the following problems have also been pointed out. That is, (c) the space volume is small (the stroke volume is small). ←) Due to the unevenness of the groove bottom of the female rotor tooth profile, it is difficult to ensure good sealing performance and it is difficult to measure dimensions during processing. Furthermore, the profile of the cutter is uneven and complicated, resulting in poor processing efficiency. (e) Since the follow-up side curve of the tooth profile is created as a point, the sealing point is likely to wear out, making it difficult to maintain the sealing effect. (f) The pressure angle of the tooth profile near the pinch circle is almost zero, making it difficult to machine with high precision and the life of the machining tool is short. Especially when hobbing a single screw rotor, the life of the hobbing tool is shortened. Note that the contact surface 18' of both tooth profiles shown in FIG. 1(a) in the initial meshing phase is approximately 20 m
Since the space 18 expands in the phase shown in FIG. It is preferable that the volume of is not large. The characteristic tooth profile mentioned above is, for example, one of the conventional tooth profiles used by other companies. In the drawings, components designated by the same reference numerals as those in FIG. 1 are the same members as those shown in FIG. 1, so their explanations will be omitted. Note that the meshing phase of the tooth profile in FIG. 2(a) corresponds to that shown in FIG. 1(b). In the figure, (1) female rotor tooth profile (a) forward curve; 28-29; circular arc with radius r'I centered on point 36 on straight line 17-29; 29-30; centered on pitch point 17; An arc of radius r'2. (b) Follow-up side curve; 30-31; epitocolloid curve formed by point 23 on the male rotor tooth profile; 31-32; part of a straight line passing through the rotation center 4 of the female rotor. 32-33; Pitch circle 16'' An arc centered at 2. 33~34; Arc centered on pictorial center 4, 34~
35; Arc having its center on the pitch circle 16. (2) Male rotor tooth profile (a) Advance curve; 21-22; Envelope by female rotor tooth profile (circular arc with radius r- centered at point 36 on straight line 17-29); 22-23; pitch point 17 An arc of radius r'2 centered at . (b) Follow-up side curve; 23-24; Ebitrochoid curve based on point 31 on female rotor tooth profile; 24-25; straight line 31
Generated curves by ~32; 25-26; arc having its center on the pitch circle 15; 26-27; a circular arc having its center on the rotation center 3; 27-21; an arc having its center on the pitch circle 15. However, the volume of the illustrated vacuum space 18 is
(b) It is much larger than the tooth profile shown. When both the female and male rotors are in the rotational position shown in FIG.
The three points 9 are in contact with each other with a slight clearance to the extent that no leakage from the working space occurs. The three contact points form a space 73 on the forward side of the tooth profile (above the X axis in the figure), while
A space 18 is similarly formed on the following side of the male rotor tooth profile (below the X-axis). On the suction end surface 67 (see Figure 3), as the rotor rotates in the direction of the arrow, the volume of the space 18 gradually expands, creating a significantly larger vacuum space as described above. Form. On the other hand, on the discharge side end face 68 (see FIG. 3) side, the space 73 gradually reduces its volume as both rotors rotate, and eventually reaches a point close to zero. Therefore, the gas trapped in the space 73 is abnormally pressurized, and
In the case of an oil-cooled rotary compressor, the lubricating oil injected for cooling, sealing, and lubrication remains in the compression space formed by the female and male rotors and the cylinder wall in the closed space, so liquid compression The state of female,
Male rotors generate abnormal vibrations and noise, which in extreme cases accelerates rotor wear and damage. Furthermore, since an excessive rotational torque is required and an excessive load is applied to the rotor and casing, power loss is large, and the service life of the bearing is shortened. In order to solve the above problems, conventional! “1 Kosho 58
214693 and Japanese Patent Publication No. 58-1.31388, the residual gas and lubricating oil are released into a separate low-pressure working space or suction side space through the bypass hole, or the volume of the bypass hole 11 is reduced. Measures have been taken to increase the size and prevent it from flowing into the low-pressure working space, but this has the disadvantage of complicating the structure and increasing costs. Purpose Therefore, the present invention is based on the first method conventionally used by the applicant.
The illustrated tooth profile has the following problems: without losing the above-mentioned advantages, or reducing the amount of the above-mentioned advantages as much as possible based on the technique of the present invention, it is possible to solve the problem mentioned above, namely, by increasing the stroke volume. The shape of the sealing point is changed to prevent abrasion and reduce efficiency over long-term use, as well as to reduce the closed space that is formed when the discharge port is closed just before the end of the discharge process on the inner wall of the discharge side casing. The object of the present invention is to provide a new tooth profile that can improve the machining accuracy and tool life of the tooth profile, and also facilitate the molding of the tool. Note that other objects and effects will be made clear in the detailed description of the present invention described below. Structure The tooth profile of the present invention will be explained below based on an embodiment shown in the accompanying drawings. FIG. 3 shows a compressor for compressible r1 fluid constructed by incorporating the screw rotor of the present invention, and its FIG. 3fa1 shows:
(1)) A-Alli! in the figure! A side sectional view along. FIG. 3(b) is a cross-sectional view taken along line BB shown in FIG. 3(a). In the figure, 1 is a male computer, which is rotatably driven by a coaxial shaft 40 connected to a prime mover (not shown), and which cooperates with a support shaft 41 extending symmetrically to the shaft 40 with respect to the computer 1. , rJ-1 to each end plate 42
The bearing portions 44 and 45 of 43 and 43 are casings that surround the outer peripheries of the rotated rotors 1 and 2, and have fluid suction at their end faces in the longitudinal axis direction. Low with 11a including n47) 1: Sen 1 section anti-42 and discharge 04B
The high pressure side end plate 43 is connected to the high pressure side end plate 43, which has rotor teeth and a groove surface. The working space 49 is created by the inner wall of the casing and the inner wall of both end plates.
form and partition. The working space 49 has a suction port 47 and a discharge port 48 that communicate with a low-pressure passage 50 and a high-pressure passage 51, respectively, for working fluid inside the casing. The cross section of the casing 46 has two cylindrical spaces arranged in parallel, and the distance between their center axes is smaller than the sum of the radii of each cylindrical space. A ridgeline 52 appears at the point where they intersect. The female rotor 2 has six grooves in which each of the spiral grooves runs along the rotation axis (longitudinal) direction and is usually twisted about 200 degrees around the axis, and most of the grooves are in the mouth groove. The shape consists of a concave curve inside the hollow. ``The male rotor 1 is usually equipped with four helical teeth,
Each rib is along the axis of rotation (longitudinal) direction, approximately 3
A twist of 00° is given. The tooth height of the fleshy strips partially extends inside the pitch circumference of the rotor, and most of the tooth height is located outside the pitch circle, and between the teeth and the adjacent fleshy strips, there is a female rotor. A groove into which the second tooth fits is provided, and the cross section of the tooth profile consists of a large, outwardly convex curve. The working space 49 is divided into a V-shape, and after the rotation of the rotor closes the communication between the suction port 47 of the low-pressure side end plate 42 and the working space, the meshing line of the teeth of both rotors moves (as the rotor rotates). As a result, the volume of the divided working space is reduced compared to that at the time of closure, and during this time the fluid is adiabatically compressed and becomes high pressure and temperature, and eventually the working space becomes Discharge port 4 bored in high pressure side end plate 43
8, a leaf 111 is formed on the high pressure chamber 51 side. During this period, the meshing between the rotor teeth and groove surfaces, the sliding surface between the casing inner wall and the sliding surface between the rotor end surface and the end plate inner surface are lubricated. To maintain airtightness (temperature increase), cooled lubricating oil is poured into the nozzle 53.
The liquid is injected into the working space through. The screw rotor of the present invention relates to a tooth profile curve of a rotor used in the above-mentioned compressor for compressible fluid. Figures 4 (a), fb), (cl and fd1) show the tooth profile curves seen in the cut section of the screw rotor of the present invention when cut along a plane orthogonal to each rotational axis. , the male rotor 3 is at its center of rotation, that is, the center of the pitch circle 15 of the male rotor tooth profile, and the male rotor 1 meshes with the female rotor 2 and rotates around the center of rotation 3 in the direction of the arrow. , the female rotor 4 is also its center of rotation, that is, the center of the pitch circle 16 of the female rotor tooth profile, and the rotor Z meshes with the male rotor 1 and rotates about the center of rotation 4 in the direction of the arrow. 17 is the pitch point, and point 3° is the vacuum space (
vacuum created space). The meshing state of the illustrated tooth profiles is such that the phase shown in FIG. Figure 4(b) shows that the male rotor 1 then rotates about 10 degrees, and the tooth profiles of both rotors come into contact 18' for the first time (on the upstream side in the direction of rotation).
FIG. 4(C) further shows a phase in which the male rotor has rotated approximately 20 degrees and both tooth profile curves are most deeply engaged, and FIG. 4(d) shows the tooth bottom of the female rotor and the male rotor. FIG. 3 is an enlarged view of the tooth profile of the tooth tips of the rotor. The tooth profile curve will be explained below based on FIG. 4(C) and FIG. 4(d). Referring to FIG. 4(c) and FIG. 4(d), the tooth profile curves in the figures are each regulated by the following conditions. Here, Af is an addendum, T)m is a dedendum, point A on the tooth profile curve is on the pitch circle 15-hi, and A2 is also a point on the pitch circle 16. (1) Female rotor tooth profile (a) Follow-up side curve: From the tooth tip to the tooth bottom side, the line touches A2-B at point A of pitch circle 16 of the female rotor. [b) A2 B2: An arc of radius R7 that lies on a straight line that touches the pitch circle 16 at point A2 and has a center 07 outside the concave shape of the tooth space. (c) B2-C2: An envelope formed by arc B, -C1, which is a part of the male rotor tooth profile curve, and A at point B.
Connect smoothly with 2-R'. (d) C'2 D'2 ; Envelope B2 C2 by arc B, -C1 which is a part of the tooth profile curve of the male rotor (point C2 on the line is also a point on straight line 3-4). And, the center 0 is on the straight line 3-4 and outside the pitch circle 16.
A circular arc with radius R8 having □. - A common tangent line with B2, Note that it is possible to connect the above C/, D/ smoothly using a gentle curve with the same radius as R3, (el B2 B2; on the straight line 3-4) It is a circular arc with a radius R1 having a center 01 and touches the curve E2-F2 at a point E2.The other circular arc with a radius R1 is a straight line 3-4 and a point D2.
Intersect at (f) B2 'F2; At point 01 on straight line 3-4, radius R2 having center O7 on the opposite side from Ol on the extension of straight line 0l-B2 that intersects the above line at angle θ6
arc of. However, it is convex towards the tooth groove side. At point F2, curve F touches -G2. 19-≦1.3. However, PCD is the pitch circle diameter of the male rotor. The smaller θ6 is, the larger the pressure angle near the pitch circle of the tooth profile curve D'2-E is. In this example, the above-mentioned ranges for R1 and θ6 are selected as ranges in which the pressure angle can be made sufficiently large and a tooth thickness sufficient in terms of strength can be ensured. There is. fg) F! -G2; A circular arc with a radius R8 having a center 08 above the straight line 02-F and outside the concave shape of the tooth space. The circular arc contacts the circular arc E2-F at a point F2, and the outer diameter of the female rotor at a point G2. (h) G, -H,; Outer diameter of female rotor, PCD
The width should be approximately X (0,004 to 0.01) m. -2〇- (2) Male rotor tooth profile (a) Follow-up side curve; along the tooth tip side, (j)
Hl-Al: Created by point H2 on the female rotor tooth profile, tangent to the male rotor root circle at point H1. (k) AI Bl; Part of female rotor tooth profile, arc A,
-Envelope by B. At point B, curve B, -C. come into contact with [1) Bt cl: An arc with a short radius R4 having a center 04 on a radial line extending from the rotation center of the male rotor, which intersects the straight line 3-4 with an angle θn at point 3. However, the angle θr6 is relatively large between 4° and 8°,
As a result, the center 04 is located far away from the straight line 3-4. It touches the curve C1-D at point C8. (m) C1-DI; An arc with radius R11 centered at point 3, curved at point D1, and touches -El. (b) Progressive side curve; from the tooth tip to the tooth root side, (nl
Dl-El; Part of female rotor tooth profile curve, curve C'2-
D--Envelope by E2. It touches curves E and -F at point E1. In the figure, the tooth profile curves D' and -E of the female rotor meet at the melting point D'2. to) E, -F, ; Part of female I7-ta tooth profile, arc E
, −F, envelope. At point F, it touches the song +IF+G+. (p) Part of FIG Umamezu rotor tooth profile, arc F, -
Envelope by G. Point G is in contact with the rotor root circle. (Q) G+ TI+: Male rotor tooth root circle. Accordingly, each of them is formed. Effect (1) By setting the center 04 of the arc B, -C, of the radius R4 on the radius line extending from the rotation center 3 of the male rotor, the tangent at that point CI can be determined with reference to Fig. 5. and the angle θ formed by the perpendicular line P with respect to the straight line a3-4. can be made smaller than θ' when the center 04 is placed on the radius line extending from the pitch point 17, and the following tooth profile curve of the male rotor is a straight line 3-4 connecting the rotation centers of both rotors.
The space 18 can be made smaller by moving farther away and approaching the tooth profile curve on the female rotor following side. (2) By selecting the angle θ- to be relatively large, the arc B is located on one radius line that sandwiches the angle θ-. -Since the center 04 of C1 is far away from the straight line 3-4,
Furthermore, the space 1B can be made smaller. As described above, as shown in FIGS. 4(b) and 4(c), since the volume expansion coefficient of one space 18 is small, unnecessary power loss due to vacuum creation is small. (3)' Also, in the conventional tooth profile shown in FIG. 2(a), just before the end of the discharge process and when the discharge port is closed, the space 73 formed on the forward side of the male rotor is The volume decreases as the rotor rotates. Therefore, the compressed gas and seal lubricating oil trapped in the space 73 are abnormally pressurized. In the tooth profile of the present invention, a space 75 corresponding to the space 73
[See Figure 4(d)] occurs during the compression process, and the lines B, -C, of the male rotor tooth profile are interposed at an angle θr'(=4' to 8°) between the straight line 3-4 and the point 3. intersecting lines 3
- a circular arc with a radius R4 having a center 04 on C1 and being far away from the center 04 straight line 3-4 (in relation to the angle θ-=4° to 8”); A common tangent between the envelope formed by the lines C/, Hl, and the arcs B and -C of the female rotor tooth profile and a circular arc with a radius R8, or a smooth curve comparable to the radius R6. With the envelope formed by the circular arc n%-E of the tooth profile 0, -0, female Accordingly, the portions formed by the envelopes of both tooth shapes are separated and the space 75 is communicated with the suction side.As a result of the above, the discharge 2 [at the pressure at the time of closing the discharge boat immediately before the end of the culm], in the space 75 1-[Over-compression of condensed gas and liquid compression are eliminated, and accompanying noise, abnormal vibration, unexpected wear, and bearing damage do not occur.Furthermore, in the conventional technology, Proposed Japanese Unexamined Patent Publication No. 58-214693, Japanese Unexamined Patent Publication No. 58-131
Bypass hole 71 as described in No. 383 [No. 2 (b)
It is possible to provide a screw compressor with a simple structure and low cost without the need to provide a screw compressor (see figure). (a) Let the curve B, -C be the envelope of the arc B, -C, and the curve -E is the curve E, - of the arc D2-E2.
Since F is a circle, the sliding surfaces of the tooth profile come into surface contact, which improves the wear resistance at that location. (5) Referring to FIG. 6, since the toothed sliding surfaces are in surface contact as described above, when lubricating oil E is supplied, the lubrication and sealing effects of the surfaces can be improved due to the wedge effect. . As described above, the wear resistance and sealing effect can be improved, and a decrease in efficiency can be prevented during long-term use of the screw rotor. (6) Referring to Fig. 7, the curve A2-B is an arc having the center 07 outside the concave shape of the tooth space of the female rotor, so when the curve B2-C2 is extended in the outer diameter region Alternatively, compared to the tooth profile in which the straight line connecting the rotation center 4 and point B2 is extended by the outer diameter 1, the profile of the cutter that cuts the rotor tooth profile tends to have a wider hem, and the pressure angle can also be increased, so the tooth profile It is possible to improve machining accuracy and extend tool life. (7) Curve 112-A2 is the tooth profile curve of one coater.Since it is a generated curve by the second point A1, the pressure angle θ2 at the tooth profile is set from the curve A2-B2 to the outer diameter (H'2 (8) Referring to Fig. 8, the pressure angle θ3 at point E2 can be made larger than the pressure angle θ'3 when the center of arc D2-E2 is at pitch point 17. , D2-E, can be increased. (9) Referring to FIG. 9, the pressure angle θ4 at point F2 of the tooth profile curve can be increased (Zθ4〉/θ '
4) The pressure angle of the curve forming B2 F2 can be increased. Therefore, damage to the side surface of the hob cutter during hobbing of the rotor tooth profile is prevented, the life of the tool is extended, and the machining accuracy of the tooth profile is improved. 00) Referring to FIG. 10, the pressure angle θ at point G2 on the tooth profile curve can be increased (Zθ.〉Zθ'5), and the pressure angle of the curve forming F2 G2 can be increased to a female rotor. Since the interval between B2 and A2 of the trailing side tooth tip is a generation curve based on the intersection point Al with the Pibichi circle on the male rotor tooth profile curve, the space volume between the rotor tooth profiles is large, and both female and male Performance can be improved because the sealing point due to rotor engagement is longer and the blowhole can be made smaller. As described above, the overall space volume can be increased to increase the amount of air, the pressure angle of the tooth profile curve can be increased, the force of the tooth profile can be increased by 1 pi [accuracy], and the tool life can be extended. (121 Conventionally, although it is an important sealing point, it is a discontinuous point.
[see reference numeral 23 in the figure], it is difficult to accurately measure the position with a caliper, a micrometer, or even with a three-dimensional measurement because the tip of the filler f is spherical. That is, the 11th
．． (1) Referring to Figure 1 and Figure 1Hc1, if there is a discontinuous point on the tooth profile curve, the position of contact with filler f cannot be determined even when measuring the same point, so the exact point of discontinuity can be determined. In this case, such a problem does not occur, making measurement easier. Therefore, it is easy to process an accurate tooth profile curve. As described above, according to the tooth profile curve of the present invention, while maintaining the advantages of the conventional tooth profile by taking care not to increase the vacuum creation space, the tooth profile at the sealing point has a surface contact structure of an arc and a curved surface, which makes it possible to use lubricating oil. By creating a wedge effect, effectively performing sealing and lubrication, reducing wear and prolonging the sealing effect, efficiency is maintained, and the discharge port on the inner wall surface of the discharge side casing immediately before the end of the discharge process. It prevents abnormal vibrations and noise that occur when closing, and also prevents addendum Af z dedendum D.
The space volume can be increased by providing m. It is possible to improve the machining accuracy, and it is not necessary to form extreme corners on the cutter profile, making the tool easy to form and durable. It is also possible to extend the time. This can extend the life of the hobbing tool and facilitate hobbing. Incidentally, even though the addendum and the dedendum are provided, the blowhole is hardly a problem in practice as shown in FIG. 4(a). - As an example shown in FIG. 4 J! Table 1 shows various radii and 611W of the tooth profile of the present invention. 1. Table 4, Brief Explanation of Drawings FIGS. 1 and 2 show the tooth profile curves of conventionally used screws and
．． (Figure 1+1 is a diagram in which the meshing phase of the tooth profile used by the present applicant is different, and the time course shifts from the one shown in Figure 1(a) to Figure 1+11). Fig. 2(a) shows another usage example;
Figure +131 is a side sectional view and a cross sectional view of a rotor machine using the screw rotor of the present invention, specifically a compressor;
FIG. 4 shows different engagement positions of the pair of tooth profile curves of the screw rotor of the present invention, and the position shown in FIG. 4(a) sequentially shifts to the state shown in FIG. 4(c). Fourth (
d) The figure is an enlarged view of the meshing tooth profile, Figures 5 to 10 are enlarged views of a part of the tooth profile to explain the characteristics of the tooth profile curve of the screw rotor of the present invention, and Figure 11 is an enlarged view of the tooth profile. , is an explanatory diagram of a method for measuring a tooth profile curve of a screw rotor according to the present invention. :1. -,,,>, ,,,,,,,,,,,,,0.
Oh. -7...';-2...Female rotors 3 and 4...rotor rotation downy hair 15 and 16...
・Pitch circle 17... Mountain... Pitch point 18...
・・・・・・・・・・・・Vacuum creation space agent
Patent Attorney Nagai 1) Hiroshi − N('1

Claims (1)

[Claims] (1) A screw rotor consisting of a female rotor and a male rotor that rotates while meshing around two parallel axes, with each tooth profile of the female rotor having its main portion formed within the pitch circle of the same rotor. In the type in which the main part of each tooth profile of the male rotor is formed outside the pitch circle of the four loaders, each tooth profile curve formed in a plane perpendicular to the rotation axis of each rotor, At least, the tooth profile groove of the female rotor is created by using the curve H, -A2 connecting the point H7 on the tip of the addendum A4 and the point A2 on the pitch circle as the point A on the male rotor tooth profile, Sequentially, A, -B
, with the center 0. on the outside of the concave shape of the same tooth space. radius R with
1 circular arc, B2-C, is an envelope by circular arc B, -C1 which is a part of the male rotor tooth profile, D, -E, is the envelope of radius R1 having center 01 outside the pitch circle of the female rotor. Arc, E, -F. Between, the center point 01 of the first arc D2-F, .
An arc of radius R7 with center O7 on the opposite side +F2-G
, a radius R8 having a center 08 on the outside of the concave shape of the tooth space.
The male rotor tooth profile is formed by forming an arc of
Let the curve TI, -A connecting between the point H1 on the tooth bottom of the dedendano xDm and the point A on the pitch circle -12 be a generating curve J- to the point T-I2 on the tooth groove of the female rotor, and sequentially, A,-
R, is a part of the female rotor tooth space between the arc A, -r (
A small radius R having the center 04 on the radial line extending from the rotation center of the male rotor between the envelope curve B and -C1 due to 2.
4 arc. And, its center 04 is far away from the straight line connecting the rotation centers of each rotor, and C, -D, an arc of radius R7 whose center is centered on the rotation center of the rotor. Between D and -E, there is a circular arc that is a part of the female rotor tooth space, -E, the envelope + ``'I '1, between the same arc E2-F, and between FIGH and A screw rotor formed by an envelope formed by an arc F2-G2, and characterized in that the female rotor tooth profile is provided with an addenda L, A(, and the male rotor tooth profile is provided with a corresponding dedendum Dm. .